Surgical stapling instruments used for applying parallel rows of staples through compressed living tissue are well known in the art, and are commonly used in transecting or reconnecting intestinal, gastric, or lung tissue.
One known surgical stapling instrument of this type has been in use for many years, and is currently available under the trade designation "The ILA Stapler", catalog #3957 by Minnesota Mining and Manufacturing Company, St. Paul, Minn., the use of which stapler is described in a publication entitled "Surgical Stapling, Gastric and Small Bowel Procedures, Volume I", ISBN 0-937433-00-4, Library of Congress Catalog Number 85-082599 available from Minnesota Mining and Manufacturing Company, St. Paul, Minn., the content whereof is incorporated herein by reference. That stapling instrument comprises first and second elongate structural members each comprising a handle part and a jaw part projecting from a first end of the handle part. The structural members have pivot means at second ends of their handle parts adapted for free engagement and disengagement in a plane normal to the directions in which the members are elongate, which pivot means afford, when engaged, relative pivotal movement of the structural members in said plane between a closed position with the jaw parts in closely spaced relationship, and an open position with the jaw parts spaced farther from each other than in the closed position. An elongate locking member having a pivot point closely adjacent a first end is mounted at its pivot point on the first end of the second structural member for pivotal movement around an axis generally normal to said plane between a locking position generally aligned with the handle part of the second structural member, and a release position with a second end of the locking member spaced from the second end of the second structural member. The first end of the locking member and the handle part of the first structural member adjacent its first end have surfaces adapted, when the pivot means are engaged and the structural members are in their open position, for engagement during movement of the locking member from its release position to its locking position to forcefully move the structural members to their closed position so that high compressive forces can be applied on tissues to be stapled between the jaw parts of the structural members, and means adapted for releasable engagement between the elongate locking member and the second structural member are provided for releasably holding the locking member in its locking position and thus maintain any compressive forces applied between the jaw parts. The stapling instrument is adapted to have a removable anvil positioned along one of the jaw parts, and a cartridge containing a plurality of staples disposed in rows positioned along the other of the jaw parts in opposition to the anvil, and the cartridge includes manually actuatable means for sequentially ejecting the staples from the cartridge to press the staples against the anvil to engage and close the staples in tissues between the jaw parts when the structural members are in their closed position. Additionally, if desired, the cartridge can include a knife that moves along and bridges between the cartridge and anvil to cut tissues between the rows of applied staples.
Typically, the lengths of the rows of staples applied by such prior art stapling instruments have been limited in length to about 50 millimeters (2 inches) because compression of tissues between jaw parts of sufficient length to apply longer rows would cause such jaw parts to deflect excessively away from each other and result in improper spacing between the anvil and cartridge, particularly near the distal ends of the jaw parts, and incomplete closure of the staples resulting in poor hemostasis in the tissues being stapled.
One proposed solution to this problem described in U.S. Pat. No. 4,429,695 has been to provide supports at opposite ends of a knife that cuts between the rows of staples, which supports are moved along the jaw parts with the knife and the means for sequentially ejecting the staples against the anvil to hold the anvil and cartridge in the proper spaced relationship as the staples are ejected and closed. The use of such supports, however, requires jaw parts of sufficiently large cross sectional area to receive them, moving such supports along the jaw parts increases the force needed to operate the stapling instrument, particularly when stapling tissue that is highly compressed so that the supports must remove deflection from between the jaw parts as it moves, and the solution only works where a knife is used to cut tissue between the rows of staples, which cutting is not desired in all uses for such stapling instruments.